Petroleum based lubricant containing a bis-phenol stabilizer



United States Patent 2 Claims. Cl. 252-42 ABSTRACT OF THE DISCLOSURE Our invention resides in the use of bis[2-hydroxy-3- (alpha-methylxylyl)--methylphenyl] methane as a stabilizer for lubricating oils and greases.

This is a division of application Ser. No. 315,368, filed Oct. 10, 1963, now US. Patent 3,318,961 dated May 9, 1967.

This invention relates to a new chemical which possesses activity as a stabilizer for lubricating oils and greases.

The chemical of the present invention is bis [2-hydroxy- 3- (alpha-methylxylyl -5-methylphenyl] methane.

The chemical of the invention is prepared by reacting p-cresol with vinyltoluene (ortho-, metaor paravinyl toluene, or mixtures of any of them) in approximately equimolar ratios to form the intermediate 2-(alpha-methylxylyl)-p-cresol. The intermediate 2-(alpha-methylxylyl) p-cresol is reacted with approximately one-half mole of formaldehyde per mole of the intermediate to produce the bis[2 hydroxy-3-(alpha-methylxylyl)-5-methylphenyl]methane having the formula:

OH OH (1313: l l (3133 Q? CH t@ H I H CH3 CH:

on i on;

The p-cresol is reacted with the vinyl toluene in the presence of a Friedel-Crafts catalyst such as sulfuric acid, phosphoric acid, boron trifluoride, boron trifluoride etherate (boron tritiuoride-diethyl ether complex), aluminum chloride, zinc chloride, etc. The resulting 2-(alphamethylxylyD-p-cresol is reacted with the formaldehyde in an acid medium, as in the presence of butylphosphoric acid (mixture of the monoand di-butyl esters of phosphoric acid), sulfuric acid, p-toluene sulfonic acid, etc., with or without a solvent such as benzene, toluene, xylene, ethylene dichloride, etc. as at the reflux temperature of the solvent, or at temperatures from 100 C. to 125 C. without a solvent. The intermediate Z-(alpha-methylxylyl) p-cresol which is reacted with the formaldehyde may be in the form of the crude reaction product of the p-cresol and vinyl toluene, or the compound may be recovered from the crude reaction product as by distillation before reaction with the formaldehyde.

The following examples illustrate the invention. All parts and percentages referred to herein are by weight.

Example 1 The 2-(alpha-methylxylyl)-p-cresol was prepared as follows:

To a mixture of 1,080 g. moles) of p-cresol and 54 g. of BF -etherate (boron trifluoride-diethyl other complex) was added 1,180 g. (10 moles) of vinyltoluene (a commercial mixture of the metaand para-isomers) at 3,388,064 Patented June 11, 1968 a rate suflicient to maintain the reaction temperature at 55-60 C. The addition required seven hours. The mixture was then allowed to stir for 16 hours at 55-60 C. Anhydrous ammonia was then bubbled through and the BF NH complex which precipitated was filtered olf. The filtrate was fractionally distilled, 2-(alpha-methylxy1yl)-p-cresol being collected as a liquid fraction, B.P. 143-155 C. at 0.3 mm., wt.864 g.

The bis[2-hydroxy-3-(alpha-methylxylyl) 5 methylphenyl]methane was prepared as follows:

A mixture of 452 g. (2 moles) of the above prepared 2-(alpha-methylxylyl)-p-cresol, 31.5 g. (1 mole) of paraformaldehyde, 9 g. of butyl phosphoric acid and 100 ml. of benzene was heated under reflux at about C. for 20 hours in a one-liter 3-neck flask equipped with a thermometer, mechanical stirrer, Stark and Dean trap and condenser. The water formed during the reaction and collected in the Stark and Dean trap amounted to 18.5 ml. (theory-18 ml). The benzene was then removed under reduced pressure and 6 g. of propylene oxide was added to deactivate the catalyst. The extremely viscous product Weighed 461 g.

Analysis.--Calculated: percent C, 85.3; percent H, 7.81. Found: percent C, 83.9; percent H, 7.90.

Example 2 This example demonstrates the usefulness of the compound of the present invention as a stabilizer for petroleum based lubricating oils. The compound may be incorporated in a concentration range of 0.1% to 2%, preferably 0.2% to 0.5% based on the weight of the lubricating oil.

The bis[2-hydroxy-3-(alpha-methylxylyl) 5 methylphenyl]methane was evaluated in a concentration of 0.3% by weight of a commercial petroleum based lubricating oil using ASTM-943 oxidation test for turbine oils. In the test, a mixture of 300 ml. of the oil and 60 ml. of distilled water is heated at C. under a water cooled condenser. Copper and iron coils are submerged in the system and oxygen is bubbled through at the rate of three liters per hour. The break point is the amount of time required for the acidity of the mixture to rise to an acid number of 2 or for heavy sludge to develop with a corresponding large increase in viscosity.

The results showed less than 7 days to break for the oil alone and 80 days to break for the oil containing the [2 hydroxy 3 (alpha methylxylyl)-5-methylbenzyl] methane.

Example 3 This example demonstrates the usefulness of the compound of the present invention as a stabilizer for soap grease lubricants. The compound may be incorporated in a concentration range of 0.1% to 3%, preferably 0.2% to 1% based on the weight of the soap grease lubricant. Such soap grease lubricants are dispersions of a minor proportion of a metallic soap in a major proportion of mineral oil, usually with a small amount, e.g. up to 5% of water. The soap may be a lithium, sodium, potassium, calcium, barium or aluminum soap derived from animal or vegetable fats, or soap-forming fatty acids, e.g. stearic, oleic, palmitic or lauric acids, or wool fat, or rosin acids, or petroleum acids, e.g. naphthenic acids. The mineral oil will consist of varying proportions of paraflinic, naphthenic, aromatic and mixed petroleum oils.

The bis[2-hydroxy-3-(alpha methylxylyl) 5 methylphenyl]methane was evaluated by mixing into a commercial lithium soaps grease at 0.5% concentration, spread ing the grease as a 30-35 mil (0.030 to 0.035") thick film on a steel plate and aging in an oven at 300 F. Degradation of the grease is demonstrated by a significant change in the physical form of the grease manifested by either flowing off the plate or hardening.

2. Petroleum based soap grease lubricant containing a minor amount of bis[Z-hydroxy-3-(alpha-methylxylyD-S- methylphenyflmethane suflicient to stabilize against oxidation.

References Cited UNITED STATES PATENTS 2,636,905 4/1953 Kehe et a1 25252 X 2,731,443 l/1956 Forman 26045.95 3,057,928 10/1962 Koblitz et a1 260-619 10 3,290,250 l2/1966 Orlotf et a1. 252-54 DANIEL E. 'WYMAN, Primary Examiner.

W. H. CANNON, Assistant Examiner. 

